Accidents involving the introduction of air emboli in the coronary or cerebral circulation paths through cardiotomy or pump oxygenator procedures can result in devastating injury. The Radiometric Air Emboli Detector (RAED) proposed here provides a non-invasive mechanism for quickly and accurately detecting the presence of air emboli in the infusion path and thus helps reduce the risk of such procedures. The goals of the proposed program are: (1) Configure the Radiometric Air Emboli Detector(RAED) into a Commercially Compatible Design (2) Verify the Effectiveness of this Technique with in-vitro Testing The Phase I program successfully adapted an existing microwave radiometry system with appropriate target antennas to 'see' air emboli traveling through plastic or glass tubing by monitoring the noise levels of the fluid/air mixture flowing through a microwave antenna (or transducer). Using this principle, transducers and associated circuitry were developed to optimally detect the presence of even very small air emboli within infusion lines. The Phase 2 program will result in a device configuration that includes a transducer that snaps-on to the fluid line and a processing module. This configuration would allow the user to easily access different size fluid lines and control operational parameters such as sensitivity to bubble size.